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This is an image of a galaxy cluster called Abell 2744.

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It’s in the constellation Sculptor. It's
also been nicknamed Pandora's Cluster.

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A bunch of galaxies that are
all gravitationally bound together.

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So you can see all of these sort of yellow
fuzzy galaxies here.

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They're all very close to each other.

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And all of these are sort of glued
together by their mutual gravity.

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So, the force of gravity
is pulling each galaxy

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towards each other galaxy
and really sticking them together.

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You can kind of think of these like
almost cities of galaxies, since there are

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so many of them
that are living in such close proximity.

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This cluster was observed as part of
the Hubble Frontier Fields program.

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That program aimed to image six
galaxy clusters with some of the deepest

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Hubble observations of a galaxy cluster
that have ever been taken.

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These are incredibly deep images.

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These are some of the deepest images
that we've ever had.

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Overall,
the goal was to really sort of understand

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the deepest physics
of how these galaxy clusters are acting

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as gravitational lenses,

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uncover what the dark matter
within these galaxy clusters are doing,

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and then get a really great
look at the galaxies behind the cluster.

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So you can see there are a lot of galaxies
in this image that are sort of stretched

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into these little blue arcs.

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These are all
gravitationally lensed galaxies,

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so they're being magnified by the gravity
of this massive galaxy cluster.

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And so that gives us a chance to see sort
of smaller, fainter objects that would

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otherwise be completely invisible
without the aid of this cosmic telescope.

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And just like a glass

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lens, it collects a lot more light
and focuses it back to our telescopes.

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So we're able to see much

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fainter galaxies than we

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otherwise would be able to
without the aid of gravitational lensing.

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This really gives us a huge boost
at being able to see sort of the smallest,

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faintest objects in the distant universe.

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With this particular galaxy cluster,
you're able

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to see galaxies that are as far back
as about 12 billion years ago.

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So we're really pushing back
to sort of the early days of the universe.

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Overall, the age of the universe
now is about 13.8 billion years.

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So 12 billion years
is sort of the early stages

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of when these galaxies
would have been forming.